Process of desulphurizing iron, steel, ferro alloy, and compositions of matter for use therein



Patentfized Apr. 28, 1925.

UNITED STA PATENT OFFICE.

DANIEL D. JACKSON, OF BROOKLYN, NEW YORK; JOSEPH D. SEARS, BLOOMFIELD,

AND- FREDERICK CON LIN,

OF WESTFIELD, NEW JERSEY, ASSIGNORS TO JOHN T.

PRATT, OF NEW YORK, N. Y.; DANIEL D. JACKSON, OF BROOKLYN, NEW YORK, AND\ JOSEPH D. SEARS, O'F BLOOMFIELD, NEW JERSEY, TRUSTEES. i

PROCESS OFDESULPHURIZING IRON, STEEL, FERRO ALLOY, AND COMPOSITIONS OF MATTER FOR USE THEREIN.

No Drawing. Application filed July 29,

To all whom it may concern:

Be it known that we, DANIEL D. JACKSON, residing in the borough of Brooklyn, city and State of New York, J osnrrr D. SEARS,

residing in Bloomfield, county of Essex, and

State of New Jersey, and FREDERICK CON- LIN, residing in Westfield, county of Union,

and State of New Jersey, citizens of the United States of America, have invented certain new and useful Improvements in Processes of Desulphurizing Iron, Steel,

Ferro Alloys, and Compositions of Matter I for Use Therein, of which the following is a specification. 1

This invention relates to v a process of desulphurizing iron, steel, and ferro-alloys, and to compositions of matter for use in such process, and aims to provide improvements therein.

We have discovered that alkal'ne-reagents, such as caustic soda, sodium carbonate, and mixtures thereof, used for desulprizing, have an eflect in removing silicon from iron, steel, etc., in addition to sulphur, and this removal of silicon is undesirable in certain cases, as where the iron, steel, etc. is to be used for casting, particularly in the manufacture of gray iron castings.

The present invention provides a process whereby iron, steel, etc. may be desulphurized by the use of alkaline reagents, and notably caustic soda, sodium carbonate, or mixtures thereof, without reduction in silicon.

The invention further provides a composition of matter for use in said process, for desulphurizing without reducing the silicon, as above set forth.

According to the presentinvention, caustic soda, sodium carbonate, or-other alkaline reagent used for desulphurizing, and preferably a mixture of sodium carbonate and caustic soda in about the proportions of 70% sodium carbonate to caustic soda (as set forth in our companion applicationSerial No. 631,925 filed April 13, 1923) and a silicon-alloy are added to the metal to be desulphurized. 3 v

The mixture of alkaline reagent and silicon-allo is conveniently brought into contact wit the metal in a ladle, the mixture 1922. Serial No. 578,485.

beingintroduced before, during or after the running in of the molten metal.

The silicon-alloy should preferably have a melting point below the temperature of the molten metal, in orderthat it may be melted by the heat of the metal. A ferro-silicon containing 60% silicon, having a melting point of about 2200 1 in admixture with the alkaline reagent, has given satisfactory results with iron and steel for casting.

The amount of the silicon-alloy to use will vary with the desiliconizing action'of the alkaline reagent employed. As the alkaline reagent has a tendency to take out more silicon from the metal, more of the silicon-al- 10y will'be required to counteract or replace the silicon removed or which would otherwise be removed, by the alkaline desulphur izing agent.

Satisfactory results in practice have been obtained when 5--20% by weight of the compound of the mixture of a ferro-silic0n al- 10y containing to silicon has been incorporated with the desulphurizing combination of about sodium carbonate and 30% caustic soda.

The amount of silicon-alloy to use in the case of different alloys and of different al kaline desulphurizing reagents is best found by experiment based on a knowledge of the desiliconizing' action of the alkaline reagent.

The silico-nalloy ordinarily takes a longer time to melt than the alkaline reagent or mixture. By introducing the silicon-alloy in admixture, or concurrently, into the receptacle of the metal with the alkaline reagent, the silicon-alloy undergoes heating along with the alkaline reagent, and consequently reaches its melting point after the alkaline reagent has to a large extent completed its work. This in practice allows the alkaline reagent and silicon alloy to be melted by the heat of the metal in a ladle or receptacle, after having been run from a melting furnace, and before the metal in the ladle cools to a point which would interfere with the proper pouring of the metal from the ladle into molds. The delayed action of the silicon-alloy in melting is also of 1 action advantage in that the desulphurizing compound may exert its full. action on the molten metal wit out wasting part of itsi'efiect by a side reaction on the SlllCOIl in the silicon alloy.

In treating iron for casting with ferrosilicon containin 60% silicon, it is found that it requires a out "3 to, 6 minutes for the ferro-silicon to melt, and this period is sometimes about as long as metal can stand in a ladle before becoming too chilled for pouring. The silicon-alloy is, however, found to have an exothermic reaction with the metal, so that its use counteracts the drop in temperature of the metal due to the use of the alkaline reagent, and enables the entire reto occur in the period in which the metal can ordinarily stand in a ladle before becoming too chilled for proper pouring.

The alkaline reagent and the silicon alloy are preferably mixed, the lower melting oint constituents fused, and formed into lhmps or flakes or cakes of convenient size. These lumps, flakes or cakes are only slightly deliquescent, safe for handling, and have the characteristics in use above set forth. A size somewhat above powder particles, and lar er, is found to very much facilitate the me ting of the composition.

Other roportions than those 5 ecifically mentioned, and other procedures t an those specifically given, may be adopted without departing from the idea of the invention.

oreover, it is understood that theinvention may be generally applied to the desulphurizing of metals.

What is claimed is:

1. A proces of desulphurizing comprising treating molten iron, steel, and ferroalloys with an alkaline desulphurizing reagent having a desiliconizing effect and a silicon-alloy. I

2. A process of desulphurizing comprising treating molten iron, steel, and ferroalloys with an alkaline desulphurizing rea cut havin a desiliconizing eifect and a si icon-alloy avin a melting point not substantially above t e melting point of the metal.

3. A process of desulphurizing comprising treating molten iron, steel, and ferroalloys with caustic soda and a silicon-alloy.

4. A process of desulphurizing comprising treating molten iron, steel, and ferroalloys with sodium carbonate and a silicona 0y.

5. A process of desulphurizing comprising treating molten iron, steel, and ferroalloys with sodium carbonate and caustic soda and a silicon-alloy.

6. A process of desulphurizing comprising treating molten iron, steel, and ferroalloys with an alkaline dcsulphurizing rcagent having a desiliconizing effect and ferro-silicon containin" in the neighborhood of 60% silicon.

A process of desulphurizing comprising treating molten iron, steel, and ferroalloys with sodium carbonate and caustic soda substantially in the proportion of 70% sodium carbonate and 30% caustic soda, and ferro-silicon containing in the neighborhood of 50-60% silicon, the amount of said ferro silicon being 5-20% of the other ingredients.

8. A process of desulphurizing comprising running molten iron, steel, and ferroalloys into a ladle or the like, and treating the metal with an alkaline desulphurizing reagent having a desiliconizing effect and a silicon-alloy having a melting point not substantially above the melting point of the metal, allowing the mixture to act for a short period, and pouring the metal while it is. still fluid enough for running into molds.

9. A composition of matter comprising an alkaline desulphurizing reagent having a desiliconizing effect and a silicon-alloy.

10. A composition of matter comprising caustic soda and a silicon-alloy.

11. A composition of matter comprising sodium carbonate and a silicon-alloy.

12. A composition of matter comprising caustic soda. sodium carbonate and a siliconalloy.

13. A composition of matter comprising caustic soda and sodium carbonate substantially in the proportions of 30% and 70% respectively, in which is incorporated ferrosilicon containin about 50-60% silicon.

In witness whereof, we have hereunto signed our names.

DANIEL D. JACKSON. JOSEPH D. SEARS. FREDK. CONLIN. 

